UC San Diego: Time-Restricted Eating Improves Cardiovascular Health for Firefighters

In a recent collaborative effort, physicians with UC San Diego Health and scientists at the Salk Institute reported a form of intermittent fasting, called time-restricted eating, improved the health of study participants who had been diagnosed with metabolic syndrome.

Specifically, the researchers looked to see how time-restricted eating would affect the health of firefighters with San Diego Fire-Rescue Department.

The new findings, published in Cell Metabolism on October 4, 2022, determined that time-restricted eating within a 10-hour eating window was not only feasible, but also helped the firefighters significantly decrease their VLDL, or “bad” cholesterol, improve their mental health and reduce their alcohol intake by roughly three drinks per week.

“We’ve shown that time-restricted eating is a feasible way for shift workers, such as firefighters, to improve their cardiovascular health and wellbeing,” says Pam Taub, MD, co-corresponding author and professor of medicine at UC San Diego School of Medicine and a cardiologist at UC San Diego Health.

Cell Metabolism cover art
The findings were published and featured on the cover of Cell Metabolism on Oct. 4, 2022. Photo courtesy of Cell Metabolism
“These findings can likely be extended to a wider population of shift workers, including food service employees, military personnel, health care staff, and others who experience abnormal sleep-wake patterns.”

According to Taub, shift workers have disruption of their circadian rhythm and have much higher risk of cardiovascular disease, and are typically excluded from clinical trials.

“Our study is one of the first to include shift workers in a clinical trial, with the goal of optimizing their health within the confines of shift work,” added Taub.

Nearly 30 percent of Americans are considered shift workers, in which the individual must stay awake for two to three hours between 10 p.m. and 5 a.m. for at least 50 days a year. Increasing sleep and reducing calorie intake are often difficult, but previous studies have suggested that time-restricted eating may offer a simple behavioral change to improve health.

Almost every cell in the body has a 24-hour biological clock that produces circadian rhythms.

Circadian rhythms coordinate with the environment, in part, by regular, timed cycles of light and dark and eating and fasting. Disruptions to these cycles, which can occur with shift work, can impact health, leading to obesity, heart disease, diabetes and cancer.

In this clinical trial, 150 firefighters from the San Diego Fire-Rescue Department used the myCircadianClock app on their phones to track their eating for three months. Half the group ate within a 10-hour window, while the other half (the control group) changed nothing and ate within a 14-hour window.

Both groups were encouraged to follow a Mediterranean diet, which is known to have health benefits. The study included both individuals who were healthy and those who were overweight or who had health conditions, such as high blood pressure, cholesterol and/or blood glucose.

“Our study showed that shift workers with high blood pressure, blood sugar or cholesterol can benefit from time-restricted eating,” says Satchidananda Panda, PhD, co-corresponding author of the study, Salk Professor and holder of the Rita and Richard Atkinson Chair. “It’s not a pill, but a healthy habit that can significantly reduce these three risks of disease without any adverse side effects.”

The study found that time-restricted eating also significantly improved blood sugar and blood pressure in firefighters who had elevated levels at the start of the study. The researchers concluded that time-restricted eating may provide even greater benefit for those at risk for cardiometabolic disease and other chronic diseases.

Taub stated future studies will expand on the results and include other shift workers, especially health care employees with metabolic syndrome.